In order to effectively monitor the wear and predict the life of cylinder liner, a nonlinear degradation model with multi-source uncertainty based on Wiener process is established to evaluate the remaining useful life (RUL) of cylinder liner wear. Due to complex service performance of cylinder liner, the uncertainty of operational environment and working conditions of cylinder liner wear are considered into the model by a random function. The probability density function (PDF) formula of RUL is derived, and the maximum likelihood estimation method is adopted to estimate the unknown parameters of PDF. Considering the evaluated parameters as the initial values, the model parameters are updated adaptively, and an adaptive PDF is obtained. Furthermore, the proposed model is compared with two classical degradation models. The results show that the proposed model has a good performance for predicting the life, and the error is within 5%. The method can provide a reference for condition monitoring of cylinder liner wear.

Abstract. The tribological properties of the cylinder liner are of great significance in reducing energy loss from an internal combustion engine's system. In order to improve the antiwear performance of the cylinder liner at top dead center (TDC), the friction and wear of the honed cylinder liner during the running-in process are investigated. Using a UMT TriboLab multifunction friction wear tester, the coefficients of friction (COFs) are analyzed under different lubrication conditions and loads, and the surface roughness and profile of the cylinder liner are obtained using a three-dimensional (3D) laser scanning confocal microscope (LSCM). The COF, roughness and surface profile are compared in order to investigate the variation in tribology parameters under different operating conditions. To monitor the COF in real time, it is predicted using the polynomial fitting method. It is shown that the COF decreases with an increase in the lubrication oil and load and that the surface profile more easily becomes smooth under dry (lubrication) conditions; this can effectively shorten the operation time during the running-in process. The polynomial fitting method can achieve an assessment of the COF with a very small standard error.

In this study, a method of surface texture is considered to improve the frictional performance of the ring-liner system (i.e. RLS) under the conditions of cylinder deactivation (i.e. CDA). To assess the effectiveness of the method, a lubrication model is developed with considerations of the liner deformation, the actual rheological properties of lubricant, and the lubricant transport. By solving the model numerically, the friction reduction effect of surface texture for the RLS under the CDA is investigated. The results show that the surface texture can improve the friction properties significantly. For a six-cylinder gasoline engine, 7.57% and 7.28% decreases in the total average friction loss and power loss are observed when the RLS under the CDA is surface textured.

No abstract